The present invention relates to a method of generating a three-phase current from a dc voltage by dc-to-ac conversion, and to an arrangement for carrying out this method.
A three-phase current generated in this manner is preferably used in variable-frequency induction motors, whose advantageous behaviour is described, for example, in "AEG-Mitteilungen 55 (1965) 2", pages 118-123.
The generation of variable-frequency alternating voltages with inverters is described, for example, in "AEG-Mitteilungen 54 (1964) 1/2", pages 89-106. In that publication it is also stated that a virtually sinusoidal current can be achieved in an inductive load, such as an induction motor, by pulse-width modulation of the inverter. To attain this frequently desired sinusoidal current, sinusoidal ac voltages are generated whose sinusoidal difference is effective in the induction motor, and whose maximum amplitude is limited by the voltage of the dc voltage source.